Catalyst recovery process



P 1945- T. w. BAKER ETAL CATALYST RECOVERY PROCESS Filed March 13, 1944 Emma Wider Jillian Elem mman chloride in many respects. f

considerably "35 Patented Apr. 17, 1945' 1,313,803 V CATALYST nucovmr rnocnss Thomas W. Baker and Julian Friedman; Dallas,

Tex.) assignors, by mesne assignments, to Socony-Vacuum Oil Company, Incorporated, New York, N. Y., a corporation of New York Application March is, isie seri i No. 526,230 14 claims. (CL' 2 396)- This invention relates to the recovery of aluminum bromide from light tars which are formed in low temperature hydrocarbon conversion processes. These tars are presumably complex compounds formed by the interaction of aluminum bromide and the hydrocarbons, and settle out as an immiscible layer. The use of aluminum bromide to catalyze a low temperature hydrocarbon isomerization process has been disclosed in U. 8.. Patent 2,288,477 to Charles W. Montgomery. The use of aluminum bromide to catalyze other low temperature hydrocarbon conversion reactions and condensation reactions has been disclosed .in-copending application Serial No. 448,886, filed June 2-9, 1942, by Will Swerdloii and Manual H. Gorin. Aluminum bromide is similar to aluminum chloride in its catalytic activity for these low temperature hydrocarbon conversion processes and ofiers the advantage over aluminum chloride in that it is soluble in liquid hfdrocarbons; Because of this solubility of aluminum bromide in liquid hydrocarbons more eihcient contacting between the catalyst and the hydrocarbon reactant is obtainable, than is possible with aluminum chloride. Also, since vigorous agitation is unnecessary by the use of aluminum bromide, it is economical to provide longer reaction time, thus making unnecessary the use of promoters such as halogen acids to increase the velocity of the hydrocarbon conversion reaction. For these and many other reasons aluminum bromide is very boiling hydrocarbons or coke.

gases were first distilled off and then the aluuseful as a catalyst, and is superior to aluminum Aluminum bromide. is, however, more expensive than aluminum chloride andlin order to be able toutilize its advantages it should be efliciently recoverable for reuse in any. process 'in which it is used as the catalytic agent, :Theremide compounds settle out from the liquid hydrocarbon reaction mixture as an immiscible, layer, and are associated with a certain amount of additional saturated hydrocarbons soluble in the catalyst-complex. The aluminum bromide tar will usually contain from 60 to 80 percent by weight of aluminum bromide. While this organic-aluminum' bromide complex apparently stillhas considerable catalytic activity, the advantage of solubilityin the hydrocarbons is lost and hence a .the'catalyst complex should be withdrawn and the aluminum bromide recovered to render it suitable for reuse.

In a copending application of Irving H. Welinsky and Manuel H. Gorin, Serial No. 459,542, filed September 24, 1942, a method was proposed ,for the recovery of aluminum bromide from light ,tarry complexes.

By method of this latter application the aluminum bromide was recovered by subjecting the tarry complex to destructive distillation. This was donby distilling the tar under conditions of total reflux of hydrocarbons boiling. above about 100 C., until the tar was reformed by the action of the heat in the presence of the catalyst to. light fixed gases, aluminum bromide and high The light fixed minum bromide was distilled off and recovered, while the heavy material not volatile at the distillation temperatures employed were retained in the still pot. I

Thepresent invention is based on experience gained in the use of this destructive distillation process for the recovery of aluminum bromide from tarry complexes and represents certain improvements on this processes will be brought out hereinbelow.

The most important of these improvements is fore, any process for the recovery of aluminum 40 concerned 'with the method of heating the tar. Heretoiore, when theyessel containing the rela Without intending to limit ourselves to any theoretical considerations, it is our belief that aluminum bromide when used as the catalytic reagent in hydrocarbon conversion processes :apparently reacts with unsaturated hydrocarbons, either present in the reaction mixture or formed in the presence of the catalyst through cracking reactions toform complex organic-aluminum halide compounds. These compounds are substantially immiscible with the hydrocarbons and therefore, are much less desirable ascatalytic 'tively cool tar was heated, the portions of the tar near the walls of the vesselheated up rather quickly, while the inner portions of the tar, :re-

mote from the walls, remained relatively cooldue to the slowness of the heat transfer through the body of the tar; Overheating of the portions of the tar adjacent the vessel walls frequently occurred resulting in the formation of a coky residue which adhered to the walls. The formation of this coky; layer was disadvantageous in that it lowered the heat conductivitywhrough the walls ofthe vessel, and made frequent cleanoperations necessary, Also, gases produced by-di'stillation from and cracldng of ,the overheated portions ofthe tar, travelled through the. body of the tar and caused bubbling and trothing as they broke the surface Due to this bubbling and frothing someof the tar was camed over agents. These complex organic-'aluminumebroe into the iractionating column, causing a decrease in the efllciency of the column and consequently a decreased recovery of the halide value of the tar. .Also, in many instances. a cl ing of the column was encountered, due to the accumulation of tar therein. By employing a slow appli- 5 cation of heat to the heating vessel, overheating of the tar was greatly minimized. However, the long period of time consumed in the heating operation tended to lessen the value of the process from an economical standpoint.

An object of the present invention is to provide an improved method of heating the tar whereby bubbling and frothing of the tar is avoided. Another object is to reduce the length of the heating period and hence the time necessary. for carrying out the recovery process. Still another object is to effect a more complete recovery of the aluminum bromide in substantially pure form. Other objects will be apparent from the following description of the invention.

stant optimum rate while the temperature of the 5 vessel is maintained within a range suitable for promoting a rapid evolution of fixed gases from the tar without substantial cracking of the tar, Thus, dissolved gases and low boiling free hydrocarbons are rapidly removed from the tar while 3'0 the tar is being quickly heated to a temperaturesuillciehtly high to initiate-the desired reforming reactions in the tar. In this way the bubbling and frothing of the tarry mass heretofore encountered is practically eliminated. When all of the tar has been admitted to the heating vessel,

the heating temperature is raised to intensify the cracking of the tar so that the aluminum v bromide-hydrocarbon complexes present in the tar are broken down to form free aluminum bro- 40 mide which is then distilled oil! and recovered. Additional light hydrocarbons also produced by the cracking reactions are readily sep rated from the vaporous stream issuing from the heating vessel by cooling the stream to condense out the-- aluminum bromide The recovery of the aluminum bromide content of the tar is made substantially complete by a further intensification of the heating temperatlne so that heavy hydrocarbons produced in the reforming reactions are even ally broken down to form fixed gases, such as hydrogen, and coke. The process also provides for the recovery of the halide value of any alkyl halides or hydrogen bromide formed in the distillation process. 5

The attached drawing is a schematic illustration of an apparatus suitable for practicing the improved process of our invention. Referring, to the drawing, the light tar settling out" as an immiscible layer from thelow temperature hvdro carbon conversion reactor (not shown) is drawn oil andsent to storage container l by way of line l'provided with control valve 3. From the stor- .agecontainer, the tar is withdrawn in line 4,

provided with a suitable control valve 5 and a pump 8 and sent to-still pot 1, the temperature of which has been previously brought up to from about 500" F. to about 625 F. The rate of feeding 02 the tar to the still pot is preferably controlled between about ion and about 200 pounds per hour per cubic foot of free space'in the still pot. Since the density of the tar is generally in'the neighborhood of pounds per cubici'oot, this means that between about 1.33' and about filled per minute. Under these conditions a rapid evolution of dissolved gases from the tar, as it enters the. pot, is efiected. Some cracking of the tar during the feeding period'takes place, however, the aluminum bromide-hydrocarbon complexes in the tar, are substantially unaffected under the temperature conditions indicated. The temperature of the still not is regulated by means of the furnace 8, provided with a blast burner 9.

When the feeding of the tar to the still pot has been completed the temperature of the pot is increased to from about 650 F. to about 850 F. to bring about an extensive cracking of the aluminum bromide-hydrocarbon complexes in the tar. Thus, atthis temperature the tar is cracked to form light fixed gases and heavy hydrocarbons, as well as tree aluminum bromide as the end products. The cracking also produces small quantities of alkyl halides and hydrogen bromide.

All of the gases and vapors formed during the feeding period as well as in the subsequent intensified cracking of the tar, are continuously withdrawn from the still pot in line l0 and passed to condenser II. The condenser is-controlled at a temperature within the range of from about 250 F. to 350 F. by means of a thermally regulated circulating oil bath (not shown) in order to condense aluminum bromide from the vaporous stream. Some of the heavier compounds produced in the initial cracking of the'tarry'complexes are not volatile under the temperature conditions obtaining in the still pot. However, some intermediary boiling hydrocarbons and hydrocarbon-aluminum bromide complexes formed during the early stages 01' the cracking operation are volatile and are carried over to the condenser where they are condensed concomitantly with the aluminum bromide.

The condensed material is withdrawn from the condenser by way of line l2, from whence it is discharged into separator ll. Here. the condensate is collected, while the remaining vapors are passed of! overhead through line I4 and directed to other units or the process to receive further treatment for the recovery of their aluminum bromide or halide value, as will be described later.

In order to tree the aluminum bromide collecting in the separator from the concomitantly condensed hydrocarbon and tar material, the condensate is recycled to the still pot T in order to subject it to further cracking. The recycling is continued only until substantially pure aluminum 5 bromide is being collected in the separator as will be evident from the white appearance of the condensat'e. A suitable window I! is provided in the separator so that the material collecting therein may be conveniently observed.

The recycling operation is accomplished as follows. Valve ll, which is normally in a closed position is opened; valve I1 being kept. closed, and

the molten aluminum bromide is withdrawn from the separator and returned to the still pot by way of lines it and 19. Line I! is-provlded with a suitable trap 20 to prevent leakage of vapors from the still not to the separator through this line.

The recycling operation is stopped by closing the' valve ll. 'The temperature of the still not is then gradually-raised to about 1400 F. and

maintained at this level until the distillation is completed in order'to crack the last traces of hydrocarbon complexes to fixed gases and coke,

thus assuring a substantially complete recovery or the catalyst salt, when distillation is com- 2.66 percent of the free space of the reactor is biota-the valve l! is opened and the product is withdrawn from the separator and sent to storage tank 2| by way of lines ll, 22 and II. a

pieces of metallic aluminum 21 of suitable size and shape to provide a large surface area for'contact with the incoming vapors. The tower is maintained at a temperature in the neighborhood of from 950 F. to 1150 F. by means of electric heaters 28 embedded in the tower walls. As the vaporous stream passes downwardly through the tower, any hydrogen bromide present therein will be converted to aluminum bromide by reaction with the metallic aluminum. Also, any alkyl halides present will be subjected to thermal cracking and will react with the aluminum metal to form additional aluminum bromide. The'reformed vaporous stream leaves the reaction tower by way of line 30, which sends it to condenser 3i. Condenser 3!, like condenser H, is maintained at a temperature within therange of from about 250 F. to about 350 F. in order to condense aluminum bromide vapors which were either formed in the contact tower or carried over from passed on in line 36, which carries them .to a water cooled sublimation chamber Til-Here.

traces of aluminum bromide vapor which have been carried over in admixture with the vapors in the stream issuing from the separator 33' are condensed on the walls of the chamber. Residual gases, such as light hydrocarbons and hydrogen, are vented from the chamber 31 through line 38. Aluminum bromide on the chamber walls is readily recovered after completion of the process run, by applying sumcient heat to the outside of the chamber walls to meltit. The molten salt is.

then withdrawn from the chamber by way of line 39, provided with the valve 40, and sent to product storage tank 2| by way of lines 39. 22 and 23.

Residual aluminum bromide vapors remaining in the still pot at the end of the run may be recovered by flushing these vapors with a hot inert as, such as methane, or some of the fixed gases from the process itself.

Suitable heating means are pr'ovided'around the melt conducting lines of the system as well asthe separators l3 and 33, in order. to prevent a possible clogging of'the system due to solidification of the molten s'alt therein. Also, it is preferable that the storage tank 2 l, as well as the. separators l3 and 33. be lined with suitable material, j

such as glass, to avoidthe corrosive action of the catalyst salt.

In feeding of the tar to the still not we have indicated a preferred rate of from about 100 to about v200 pounds per hour per cubic foot of volume of the pot. Employment of slower rates at the heating temperatureindicated would be intemperature was increased after the feeding was completed.

Atemperature of ma 500 n. to 625 h s 4 preferably employed in the still pot during the 5 feeding period, because. temperatures below 500 F. do not provide sumciently rapid distillation of light gases from the tar, although use of lower feeding rates .than we have indicated would, of course, allow use of somewhat lower heating temperatures. However, the feeding operation is most elilcient when the tar is admitted to the pct at .thefastest rate consistent with rapid, complete. removal of dissolved fixed gases without substantial crackingof the tar. This necessitates the employment of the highest temperatures which will not cause extensive-cracking of the tar, aswell as the use of the highest feed rates which will allow complete removal of the fixed gasesfrom the tar. On the other hand, if the still pot is. maintained above 625 F. during the feeding period. a flashing oil of unreacted portions of the tar from thepot takes place. This flashing off of the tar may cause a clogging of the system and invariably resuits'in'ga decreased percentage of catalyst recovery.

We have indicated a preferred temperature range of from 650 F. to 850F'. for thecracking- -of the tarry complexes becausegin this range violent cracking of the tar is avoided. and the reforming reactions take place atarate which is favorable for the recovery of the catalyst from the gaseous stream evolving from the heating vessel. Thus, employment of higher temperatures tend to flood the system with gases formed by very rapid cracking'of the tar, so that emciency of product recovery is decreased. The final heating to about 1400f F. after the main portion of the tar has been cracked, serves to break up any larger, more stable aluminum bromide-hydrocarbon complexes and usually re= sults in an increased recovery of catalyst of from 10 to percent. Although temperatures as high as 1600" F have been employed, generally temperatures above' 1400 F. give only an insignificant increase in the'amount of catalyst recovered.

Use of temperatures in the neighborhood of 950 F. to 1150 F. in the aluminum tower serves to 'still further increase the catalyst recovery since temperatures of this order are capable of breaking down alkyl halides which are produced in the initial cracking and which are not condensible in condenser l3.

Ordinarily, .the still 'pot will be constructed of iron or steel, and it is therefore recommended that suflicient metallic aluminum be added to the pot, prior to the admission of the tar, to prevent the formation of iron ibromides'therein. For this purpose the use of aluminum shavings, to give a large surface to volume ratio, is desirable. In fact. by adding suflicient aluminum-to the still pot it is possible that all of the bromine, hydrogenand alkyl bromides formed may be reacted to form aluminum bromide. However, we prefer to 'pass the gases evolved from the still pot. through In order to illustrate the results obtainable by our improved method for recovering aluminum bromide catalyst i'rom tarry complexes, the following example is given:

Imple The. tarry residue settling out of the liquid phase allrylation reaction which was catalyzed by aluminum bromide, was drawn oil for recovery of the catalyst therefrom. The tar was ahalyzed and showed a. bromine content of 69.6 weight percent, or an aluminum bromide content 0177.5 weight percent. 2788 grams of this tar were led to a still pot, enclosed 'in an electric iumace which was maintained at 'an average temperature of 530 F. during the feeding period in order to drive oi! the light fixed gases from the tar. All of the tar was charged to the still pot in a period of 60 minutes.

This corresponds to a feed rate of 122 pounds per hour per cubicfoot of internal reactor volume for the reactor used. The temperature of the still pot was then increased slowly for 49 minutes. At the end of the run the still pot had attained a temperature of 1590 F. which temperature was maintained for 7 minutes before terminating the run. The main portion of the aluminum bromide was distilled over within the temperature range offrom 700 F. to 800 F.

All of the vapors'and gases formed in the still not during the feeding period and that produced by the cracking reactions at the higher temperatures, were passed through a condenser which was controlled at an average temperature of 304 I". Here, free aluminum bromide together with some intermediary boiling bromine compounds were condensed from the vaporous stream. From the condenser the mixture was passed to an aluminum vapors were then condensed and passed to a second separator where additional aluminum bromide was collected. .The overhead vapors from this separator were then sent to an aluminum last traces of catalyst salt.

The amount of aluminum bromide collected in aavasos pounds. a still higher recovery of catalyst from the tar would be attained.

Having fully disclosed our invention, and having described the advantages thereof, what wedesire to be secured by Letters Patent is:

1. A process or recovering aluminum bromide from tarry masses formed in hydrocarbon conversion processes which employ aluminum bromide as a catalystic agent which comprises the steps of (1) introducing the tarry mass into a heating zone at a substantially constant rate. while maintaining the temperature of said zone at a sufliciently high-level to cause a rapid evelution of gases from said tarry mass without substantial cracking of the mass, (2 increasing the intensity of heating in said zone, after the introduction of said tarthereto has been completed,

so as to crack the aluminum bromide-hydrocarbon complexes present in the tarry mass to form free aluminum bromide, and (3) recovering-the aluminum bromide.

mide as a catalytic agent which comprises the steps of (l) introducing the tarrymas's' into a heating zone at a substantially constant rate,

.bromide sublimation chamber for recovery of the the first separator was 1876 grams or 87.0 percent.

of the total content of the tar treated. 171.6 grams or 7.9 percent were collected in the second separator. An additional 40.4 grams, or 1.8 percent of the catalyst was deposited in the sublima- Thus, there was a total or 96.8-

.tion chamber. percent of catalyst recovered in a practically chemically pure form.

p te analyses Oftho products collected in the two separators and in the sublimation chamber indicated that the catalyst in the first separator was the least pure, having an aluminum bromide content of 98.4 percent. O n thc'basis of this figure alone, a total recovery of 95.3 percent of pure aluminum bromide was obtained.

An additional 1.6 percent of aluminum bromide was determined to be present inthe coke-like resicatalyst was held up in the condensers and contact tower.

These results indicate that in large scale opcr stion, after the equipment had become saturated with aluminum bromide 'and other brominecom- "T of sold me within the range 0! from about 500 while maintaining the temperature of said zone at a. sufliciently high level to cause a rapid evolution of gases from said tarry mass without substantial cracking of the mass, (2) increasing the intensity of heating in said zone, after the introduction of-said tar thereto has been completed.

so as to cause cracking of the aluminum bromide-hydrocarbon complexes present in the tarry mass, (3) passing the vapors produced in said heating zone to a cooling zone to condense aluminum bromide therefrom, (4) passing the remaining vapors from step 3 to a reaction zone wherein they are contacted with metallic aluminum at an elevated temperature to form additional aluminum bromide, (5) cooling the reformed vapors from step 4 to condense substantially pure aluminum bromide therefrom, and (6) recovering the aluminum bromide condensed in steps 3 and 5.

3. A process of recovering aluminum bromide from tarry masses formed in hydrocarbon'con-r versio'n processes which employ aluminum bromide as a catalytic agent which comprises the steps of 1) introducing the tarry mass into a heating zone at a. rate such that the volume of tarry mass introduced thereto per minute is between about 1.33 and about 2.66 percent of the total volume of said zone, while maintaining the temperature of said zone at' a level sufllciently high to cause a rapid evolution of gases from the tarry mass as it enters said zonewithout inducing substantial cracking of said mass (2) increasing the intenslty of heating in said zone, after the introduction of said tarry mass thereto has been completed, so as to cause extensive cracking of the aluminumbromide-hydrocarbon complexes present'in the tarry mass, to form free aluminum bromidepand (3) recovering the aluminum bromide. g

4. A process of recovering alpminu'r'nlbromide from tarry masses formed in hydrocarbon conversion processes which employ aluminum bromide as a catalytic-agent which comprises the steps 01- ('1) introducing the'tarry mass into a heating zone at a rate or from about 100 toabout 200 pounds per hour per cubic' foot or free volume of said none whilemsintaining the temperatme to cause extensive cracking of the aluminum bromide-hydrocarbon complexes Present in said mass, to form free aluminum bromidegand. (3) recovering the aluminum bromide.

5. A process of recovering aluminum bromide from tarry masses formed in hydrocarbon conversion processeswhich employ aluminum bromide as a catalytic agent which comprises the steps of (1) maintaining a heating zone at a temiacature of from about 500 F. to'about 625 F.

while feeding the tarry mass into said zone at a rate such that the volume of said mass being fed thereto per minute-is equal to from about 1.33 to about 2.66 percent of the total volume thereof, (2) increasing, the temperature of said zone to from about 650 F. to about 1600 F., after the feeding period has been terminated, to substantially completely crack the aluminum bromide hydrocarbon complexes present in said mass, and (3) recovering the aluminum bromide formed.

'6. A process of recovering aluminum bromide from tarry masses formed in hydrocarbon-conversion processes which employ aluminum bromide as a catalytic agent which comprises the steps of (l) maintaining a heating zone at a temperature of from about 500 F. to about 625 F. while feeding the tarry mass into said zone at a rate such that the volume of said mass being fed thereto per minute is equal to fromaboutl.33 to about 2.66 percent of the total volume thereof, (2) increasing the temperature of said zone to from about 650 F. to about 1600 F., after the feeding period has been terminated, to substantially completely crack said mass, ('3) passing the vapors produced in said heating zone to a, cooling zone to condense aluminum bromide therefrom, (4) passing the remaining vapors from step 3 to version'processeawhich emplo aluminum bromidejas a ,catalytic agent which comprises the steps of (1) admitting the tarry mass to a heating zone. Gila rate such that the volume of tar introduced thereto per minute is from about 1.33 to about 2.66, percent of the total; volume of said zone while controlling the temperature of the zone within arange of from about 500 F. to about 625 R, (2) increasing the temperature within said zone after admission of the tarry mass thereto has been completed to cause an extensive crackof said tarry mass to form a vaporous mixture containing I free aluminum bromide, (3) passing the vapors from step 2 to. a cooling zone to condensealuminumbromide therefrom, (4) passing the remaining vapors from step 3 to a reaction a reaction zone wherein they are contacted with metallic aluminum at an elevated temperature to form additional aluminum bromide, (5) passing the vapors from step 4 to a cooling zone to condense substantially pure aluminum bromide therefrom, and (6) recovering the aluminum bromide condensed in steps 3 and 5.

7. .A process of recovering aluminum bromide from tarry masses formedin hydrocarbon con-. version processes which employ aluminum bro-, mide as a catalytic agent which. comprise the steps of (1) maintaining a heating zone at a temperature of from about 500 F. to about 625 F. while feeding the tarry mass into said zone at-a rate such that the volume of said mass being. fed thereto per minute is equal to from about 1.33 to about 2.66 percent of the total volume thereof, (2) increasing the temperature of said zone to from about 650 F. to about 1600" F., after the feeding period has been terminated, to substantially,

completely crack the aluminum bromide-hydrocarbon complexes present in said mass, (3) passing the vapors produced in said heating zone to a cooling zone to condense aluminum bromicle therefrom, (4) passing the uncondensed vapors from step 3 to a reaction zone wherein they are subjected to a temperature of from about 950 F. to about 1150 F. in the presence of. metallic .aluminumto form additional aluminum bromide, (5) passing the vapors from step 4 to a cooling zone to condense substantially pure aluminum bromide therefrom, and (6) recovering the aluminum bromide condensed in steps 3 and 5.

8. A process of recovering aluminum bromide trom tarts masses formed in hydrocarbon conzone wherein they are contacted with metallic aluminum at an elevated temperature to form additional aluminum bromide,(5) passing the rem nes" vapors from step 4 toa coolingzone to condense substantially pure aluminum bromide therefrom, and (6) recovering the aluminum bro-' mide condensed in steps 3 and 5.

9. A ,'p'ro'ce'ss of recovering aluminum bromid from tarry masses formed in'hydrocarbon conversion processes which employ aluminum bromide as a catalytic agent which comprises the stepsof (l) introducing the tarry mass into a heating zone ata substantially constant rate, while maintaining the temperature of said zone at a sufliciently high level to cause a rapid evolution of gases from said tarry mass without substantial cracking of the mass, (2) increasing the intensity of heating in said zone, after the introduction of the tarry xriass thereto has been completed, so as to cause cracking of the aluminum bromidehydrocarbon complexes present in said mass, (3) passing the vapors produced 'in said heating zone t'o'a cooling zone to condenseamixture of aluminum bromide and hydrocarbons therefrom, (4) recycling the condensed mixture'from step 3 to said heating zone until substantially all of the hydrocarbons and aluminum bromide-hydrocardon complexes originally present in the tar have broken down to fonn'f'ree aluminum bromide, light fixed gases and coke, (5.) continuing to cool the vapors from said heating zone after heating zone at a substantially constant rate,

while maintaining the temperature of said zone at a sufliciently high level to cause a rapid evolution of gases from said tarry mass without substantial cracking of the mass, (2) increasing the intenslty oi heating in said zone, after the introduction of the tarry mass thereto has been completed, so asto cause cracking of the aluminum bror'nide-hydrocarbon complexes present in said mass, (3) passing the vapors ,producedin said heating zone to a. cooling zone to condense a mixture of bromide and hydrocarbons therefrom, (4) recycling the condensed mixture from step, 3 to saidheating zone until substantially all of the hydrocarbons and aluminum bromide hydrocarbon complexes originallypresent in the. tarIhave been broken down to form free aluminum, bromide, light fixed gases and coke,

(5) continuing to cool the vapors from said heatbromide condensed in steps and q.

11. A process for the recovery of aluminum bromide from tarry masses containing complexes of aluminum bromide with hydrocarbons which complexes are formed in low temperature hydrobro'mide as the catalyst agent, comprising the steps of: (l) admitting the'tarry mass to a heating zone at a rate of from about 190 to about 200 pounds per hour per cubic foot or tree volume in said zone while controlling the temperature of the zone within a range of from about too" F. to about 625 F., (2) increasing the temperature within said zone after admission oi the tarry mas thereto has been completed to carbon conversion processes using ahuninum crack the alumimnn bromide-hydrocarbon complexes present in said mass, (3) passing the vapors produced in said heating zone to a cooling zone to condense a mixture of aluminum bromide and hydrocarbons therelrom, (4) recycling the condensed mixture from step 3 to said heating zone until substantially all of the hydrocarbons and aluminum bromide hydrocarbon complexes originally present in the tar have been broken down to form free aluminum bromide, ht fixed gases and echo, (5) continuing to cool the vapors from said heating zone after the recycle ha been stopped to condense substantially pure aluminum bromide therefrom, (6) passing the remaining vapors from: steps 3 and 5 to a reaction zone whereinthey are contacted with metallic aluminum at an elevated temperature to form additional aluminum bromide, (7) coolmg the vapors from step 6 to condense substantially pure aluminum bromide therefrom. and (8) recovering the aluminum bromide condensed in steps 5 and '7.

12. A process for the recovery of bromide from tarry masses containing complexes of aluminum bromide with hydrocarbons which complexes are formed in low temperature hydrocarbon conversion processes using aluminum bro-v mide as the catalyst agent, comprising the steps apropos remaining from steps 3 and 5 to a reaction zone wherein they are contacted with metallic alumi num at a temperature of from about 950 F to about 1150' F. to 1mm additional aluminum bromide, ('7) cooling the vapors from step 6 to condense substantially pure aluminum bromide therefrom, and (8) recovering the aluminum bromide condensed in steps 5 and l.

13. A process for the recovery of aluminum bromide from tarry masses containing complexes of aluminum bromide with hydrocarbons which complexes are formed in low temperature hydro= carbon conversion processes using aluminum bro mide as the catalyst agent, comprising the steps oi: (l) admitting the tarry mass to a heating zone at a rate of from about 100 to about 2&0

pounds per hour per cubic foot of free volume in said zone while controlling the temperature of cycling the condensed mixture from said cooling catalytic agent which comprises the steps of (1) A admitting the-tar to a heating zone at a rate such aluminum 01: (1) admitting the tarry mass to 'a heating f zone at a rate of from about 100 to about 200 pounds per hour per cubic foot of free volume in said zone while controlling the temperature of the zone within a, range of from about'fiflblffl. to about "625 F'., (2)'increasing the tempera'turewithin.

said zone after admission of the tarry mass thereto has been completed to crackthe aluminum bromide-hydrocarbon complexes'present in said mass, (3) passing the vapors produced in said heating zone to a" cooling zone to condense a mixture'of aluminum bromide and hydrocarbons therefrom, (4) recycling the condensed mixture from step v3 to said heating zone until substantialiy all or the hydrocarbons and aliuninum. bromide-hydrocarbon complexes originally present in the tar have been broken down to form free a bromidc,'1isht fixed cases a coke, (5) continuing to cool the vapor; from said-heating zone after the recycle has been stopped to pure aluminam bromide thererrcm, (6) the vapors that the volume of tar introduced thereto per minute is from about 1.33 to about 2.66 percent of the total volume of said zone while controlling the temperature of the zone within a range of from about 500 F. to about 625 F., (2) increasin the temperature within said zone to from about 850 F. to about 1600" R, after admission or the tar thereto has been completed, to substantially completely crack said tar, (3) passing the vapors produced in said heating zone to a bromide theretrom, 6) passing the uncondensed vapors from steps 3 and 5 to a reaction zone wherein they are contacted with metallic aluminum at a temperature of from, about 950 F. to about 1150' F. to form additional alumimrm bromide, ('1) cooling the vapors from step 6 to condensev substantially pure aluminum bromide therefrom, and (8) recovering the aluminum bromidecondensedinstcps5and'i.

moms w. mm; roman 

